Siren sound sychronized light bar system

ABSTRACT

A light bar system for a motor vehicle includes a plurality of forward-facing lights and a plurality of rear-facing lights transversely spaced on a bar across a motor vehicle, the forward-facing lights sequentially operated in a pattern moving from one light to the next light in a pattern in a preferred direction, and the rear-facing lights simultaneously operated in a pattern moving from one light to the next light in a pattern in the direction opposite the forward-facing lights. 
     The lights are sequentially operated in patterns generated from varying audio frequencies of a siren signal generator producing wail or yelp signals of changing frequency, wherein selected lights are switched on at selected frequency bands in the changing frequency siren signal, and at least one specific forward-facing light and one specific rear-facing light in the light bar are energized at each selected frequency band.

BACKGROUND OF THE INVENTION

The present invention relates to light bars for emergency vehicles, suchas police cars, ambulances and fire trucks. Presently known light barsemploy various combinations of fixed lights, rotating lights or rotatingreflectors, to produce flashing light images to attract the attention ofmotorists on the highway. They also include one or more sirens to warnthe motorist of the approaching emergency vehicle.

These electromechanical devices involve drive motors, slip rings, gears,bearings and ladder chains; all of which have limited life and presentsome severe field reliability problems, particularly in very high or lowtemperatures. In addition the motor brushes and slip rings producearcing in normal operation that must be filtered out of any radiosignals.

The single function of the light bar is to communicate some form ofcommand to the motorist. This is of critical importance in terms of bothpublic safety and officer safety. Present light bars simply display ajumble of flashing lights of very short flash duration. The motoristoften does not even see an emergency vehicle immediately behind him, andit is commonplace for a police car to follow a motorist for miles withthe light bar and siren on, only to have the motorist say he did notnotice the police car at all. In a well sound-proofed car, with curvedand tinted windows rolled up and a stereo playing, it is often a truestatement.

If and when a motorist does see the lights of an emergency vehiclebehind him he has no idea of what he is supposed to do. If he is drivingin one of the center lanes of a freeway, he doesn't know whether to pullover to the left or right shoulder, or stop right there.

If the motorist sees a light bar operating ahead, he also doesn't knowwhether to stop, pass on the right, or pass on the left. A much fearedoccurance is when the decision is made too late, and the motorist simplyplows into the emergency vehicle or other vehicles in an accident.

Prior art light bar controls are fairly complex, and have little logicalcorrelation between the manipulation of the controls, the operationdesired of the light bar system, or the operational functions beingperformed. It takes an experienced operator that is familiar with thecontrols of a specific system to work the controls without looking atthem. This can be very hazardous in terms of both public safety andoperator safety. The operator often has to initiate or change light baroperation under extreme duress of conditions involving high speeddriving, radio reception and transmission, keeping track of andreporting location and direction, driving in adverse weather, andwatching both suspects and bystanders. Glancing down at the light barcontrol for a fraction of a second can be hazardous or fatal to theoperator and others.

Prior art light bar controls also leave many operational decisions up tothe individual in the emergency vehicle, and he therefore decides on thespur of the moment what mode of light and siren operation to use inpursuit, moving through freeway or highway traffic, crossingintersections, pulling over a suspect, over taking a vehicle,controlling traffic, stopping a vehicle, etc. This practicallyeliminates standardization of operational procedures, making trainingmore difficult, and increasing potential liability for the operator'semployer.

SUMMARY OF THE INVENTION

A primary purpose of the present invention is to provide a light barwith improved visibility, and greater attention-gaining power. It isanother purpose of the invention to provide a light bar having theability to direct the observing motorist to take some specific action.It is another purpose of the invention to provide a light bar havingoptional modes of traffic directing operation in which the modeselection is pre-programmed in accordance with department policies by aninternal computer. It is another purpose of the present invention toprovide a light bar in which the visual pattern of the lights is mademore evident by synchonizing the lights with the sound of a siren. It isanother purpose of the present invention to provide a light bar having acontrol with simple, logical and tactile operation that is closelycorrelated with the functions of the light bar system and consistentwith standardized department operating procedures for emergencyvehicles, and in which the controls are integrated with normal vehiclefunctions, such as the horn and turn signal indicators.

The achievement of the foregoing purposes of the invention isaccomplished by providing a light bar system for an emergency vehiclehaving a fixed row of forward-facing lights and a fixed row ofrear-facing lights arranged across the width of a light bar mountable onthe vehicle. The forward-facing lights are operated in a pattern movingfrom one light to the next in a preferred direction, and the rear-facinglights are operated in a pattern moving from one light to the next inthe direction opposite that of the forward-facing lights.

The light patterns are driven by a frequency modulated ramp generator,optionally driving an acoustic siren, and producing an electrical rampsignal of changing frequency. Specific lights in the light bar areenergized in a sequence through selecting a series of time-spacedfrequency bands in the changing frequency ramp signal, and operating atleast one specific forward-facing light and one specific rear-facinglight in the light bar at each selected frequency of the ramp signal.

In this arrangement the ramp generator drives the siren, and the lightpatterns of the light bar move in synchronism with the sound of thesiren. Therefore the motorist has his visual image reinforced with asimultaneous audio image, increasing his sensitivity of perception bycombining two senses.

In addition, the perceived visual pattern gives the motorist somecommunicated instruction and conveys a number of unambiguous commands tothe motorist. The specific commands are selected by operation of a pairof joy-stick switches, one for light control and one for siren control,with the joy-stick commands modified by the operation of other vehiclecontrols, such as the horn and turn signal indicators.

A preferred embodiment provides for the selection of siren modes andvisual patterns to be made in accordance with department policy, by theprogramming of a computer control in the form of a light selectionprogrammer, whereby the department can determine the use of siren wailor yelp modes, and can establish the light bar sequences best suitingtraffic conditions for their jurisdiction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional schematic block diagram of a light bar systemaccording to the invention; and

FIG. 2 is a programmed light pattern for the operating modes of thelight bar system of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

In FIG. 1 a light bar 1 is shown connected to a siren 2, a control head3 and a motor vehicle 4. Light bar 1 is provided with an elongatedstructural bar 6 mounted perpendicular to the length of motor vehicle 4,and supporting a plurality of lights 7, including a row of spacedforward-facing red, blue or amber lights F1, F2, F3, F4, F5, F6, F7 andF8; and additionally supporting a row of spaced rear-facing red, blue oramber lights R1, R2, R3, R4, R5, R6, R7, and R8. At the left-hand end ofthe structural bar is a left-oblique-facing left-hand clear take-downlight TL, and a left-facing clear alley light AL. At the right-hand endof the structural bar is a right-oblique-facing take-down clear lightTR, and a right-facing clear alley light AR.

Control head 3 is provided with a light control joy-stick switch 10having a centrally detented off position 11 and four detented orthogonalon positions; "PURSUIT" position 12, "TAKE-DOWN" position 13, "PARK"position 14, and "REAR ONLY" position 15. Control head 3 is alsoprovided with a siren control joy-stick switch 20 having a centrallydetented off position 21 and four detented orthogonal on positions;"SIREN" position 22, "P.A." position 23, "RADIO" position 24 and "HORN"position 25. Operation of light control switch 10 also closes switch 16and/or operation of siren control switch 20 closes switch 26, supplyingvehicle power 29 to a siren ramp generator 30, which produces arepeating audio frequency pattern of continuously variable frequencytypically in the range from 20 Hz to 2000 Hz. in the form of either anincreasing, then decreasing wail mode, or a repeating increasingsaw-tooth frequency modulation yelp mode.

The siren ramp generator 30 supplies the siren signal to the "SIREN"contact 22 and placing the siren control 20 in the "SIREN" positionconnects siren ramp generator 30 to a siren amplifier 35, whichmodulates vehicle power 29 to a siren speaker 36. Placing siren control20 in the "P.A." position 23 connects the vehicle radio microphone 40 tothe siren amplifier 35, permitting the officer to utilize the sirenspeaker 36 as a public address system. Placing the siren control 20 inthe "RADIO" position 24 connects the siren amplifier 35 to the vehicleradio receiver 41, permitting the operator to utilize the siren speaker36 to produce the audio of incoming radio transmissions. Placing thesiren control 20 in the "HORN" position 25 connects the siren amplifier35 to a horn siren gate 44, which is connected in turn to siren rampgenerator 30; permitting the operator to momentarily operate the sirenby pressing the vehicle horn button 42, closing the vehicle horn relay43 and operating the siren concurrently with the vehicle horn 45.

A ramp rate doubler 46 is connected between the vehicle horn relay 43and the siren ramp generator 30. Ramp rate doubler 46 commands sirenramp generator 30 to produce double the number of wail or yelp patternsper unit of time as long as the vehicle horn button 42 is depressed.This function provides a visual and audio pattern change for traversingintersections or other local hazardous locations.

The siren ramp generator 30 also supplies a siren signal to a frequencydivider 50 which divides the frequency spectrum into a number of bands51a through 51j, with each band connected to a respective input to alight selection programmer 52, selectably connecting each of frequencybands 51 to one or more lights 7. Selection of the light pattern at eachband of the frequency spectrum is made by operation of the light control10. Placing the light control switch 10 in the central off position 11makes the light bar inoperative. Moving the control 10 to any of theorthogonal mode positions closes a light enable switch 16 to energizethe siren ramp generator 30.

Placing control 10 in the "PURSUIT" position 12 selects a code patternin the light control coder 60, which provides a command to a lightcontrol decoder 61 which selects a light pattern program in the lightselection programmer 52 by any of a number of conventional means, suchas ring counters, stepping switches or and-gates whereby any light 7 maybe programmed to operate at any selected frequency band 51 for eachlight control 10 operating mode 12, 13, 14 or 15.

A typical pursuit pattern programmable is a "handclap" mode in which thelight pattern moves from the center of the light bar to the ends andback to the center. Since the light selection programmer 52 is driven bythe siren ramp generator 30 through the frequency divider 50, the lightpattern is synchronized with the siren ramp generator frequencyspectrum, whereby typically the center lights F4, F5, R4 and R5 are onat a low siren frequency band; F3, F6, R3 and R6 are on at the nexthigher frequency band; F2, F7, R2 and R7 are on at yet the next higherfrequency band; F1, F8, R1 and R8 are on at still the next higherfrequency band; and TL, TR, AL and AR are on at the highest frequencyband. This mode provides a visual command sweeping the light patternfrom the center to the sides, instructing vehicles both in front and tothe rear to move aside in either direction.

Another optional pursuit pattern that is programmable is abi-directional sweep pattern in which either the forward-facing orrear-facing lights sweep back and forth from one end of the light bar 1to the other end.

Since the motion of the light pattern is synchronous with the siren rampgenerator 30, placement of the siren control 20 in the siren position 22energizes the siren speaker 36 through the siren amplifier 35. Thereforethe motion of the light pattern is also synchronous with the sirenaudio, providing both visual and audible stimuli to observers, andimproving the threshold of recognition of the emergency vehicle.

If a police car moving through traffic in the pursuit mode comes upbehind a suspect the officer wishes to pull over to the left, theofficer places the police vehicle's turn signal control 65 in the leftturn position 67. This energizes the vehicle's left-turn indicator 71,giving a command to the light control coder 60, and the light controldecoder 61 to select an operating mode in the light selection programmer52. A typical programmed pattern would then sequence the forward-facinglights in a pattern wherein light TR is on at the lowest siren frequencyband, lights F8 through F1 are sequenced on at successively higherbands, and TL is on at the highest frequency band. The suspect wouldthen observe a sweeping pattern from right to left, commanding him topull over to this left. At the same time the rear-facing lights aresequenced in the opposite direction, with light AL on at the lowestfrequency band, R1 through R8 are sequenced on at successively higherbands, and AR is on at the highest frequency band. Overtaking motoristswould then be instructed by the light pattern to pass to the right ofthe police car.

Similarly, if a police car moving through traffic in the pursuit modecomes up behind a suspect the officer wishes to pull over to the right,ad officer places the police vehicle's turn signal control 65 in theright turn position 66. This energizes the vehicle right-turn indicator70, giving a command to the light control coder 60, through the lightcontrol decoder 61 to select an operating mode in the light selectionprogrammer 52. A typical programmed pattern would then sequence theforward-facing lights in a pattern wherein light TL is on at the lowestsiren frequency band, lights F1 through F8 are sequenced on atsuccessively higher bands, and TR is on at the highest frequency band.The suspect would then observe a sweeping pattern from left to right,commanding him to pull over to this right. At the same time therear-facing lights are sequenced in the opposite direction, with lightAR on at the lowest frequency band, R8 through R1 are sequenced on atsuccessively higher bands, and AL is on at the highest frequency band.Overtaking motorists would then be instructed to pass to the left of thepolice car.

Once the officer has pulled the suspect vehicle over to the right, theofficer may move the light control switch 10 to the "TAKE-DOWN" position13. Typical programming for this mode would maintain the rear-facinglights in the left-hand sweep, with the vehicle's turn signal control 65in the right turn mode to maintain the pass-on-the-left mode describedabove, would turn on a steady forward-facing light F1, and turn on theright-hand take-down light TR to illuminate the suspect vehicle.

If the officer has pulled the suspect vehicle over to the left, usingthe "PURSUIT" position 12 the officer may move the light control switch10 to the "TAKE-DOWN" position 13. Typical programming for this modewith the vehicle's turn signal control 65 in the left turn mode wouldmaintain the rear-facing lights in the right-hand sweep,pass-on-the-right mode, would turn on a steady forward-facing light F1,and turn on the left-hand take-down light TL to illuminate the suspectvehicle.

Operation of the light control switch 10 in the "TAKE-DOWN" position 13with the turn signal control 65 neutralized may be programmed to operateboth take-down lights TR and TL, and may also include both alley lightsAR and AL to illuminate a wide area, with the forward and rear facinglights 7 in any mode programmed to conform to department policy.

Light control 10 is also provided with a "PARK" position 14, whichoperates the light selection programmer through the light control coder60 and decoder 61, to operate the light bar in a power-conserving mode.This usually operates only one steady forward-facing light, such as F1,and one rear-facing blinking light, such as R1. The number of lights maybe anything programmed by department policy for a mode in which thevehicle may be operating for extended time with the engine off or atidle.

An additional position of light control 10 is the "REAR-ONLY" mode. Thismode is programmed to omit all forward facing lights 7 in the light bar,but operate any desired pattern programmed by light selection programmer52 for the rear-facing lights R1 through R8. This is a needed mode formoving through freeway traffic without the hazards of having a number ofmotorists attempting to change lanes to get out of the way.

In FIG. 2 a program matrix is shown in which the operation of all lights7 is shown for each frequency band 51 for the light bar modes 12, 13, 14and 15; and turn signal contacts 66 and 67. This matrix is only typical,and each specific function is programmable to conform to an individualdepartment policy.

The foregoing describes a siren and light bar that achieves the purposesof the invention by providing a system in which the lights and sirenprovide mutually-reinforcing stimuli to improve perception of observers.The system according to the invention has simple, logical, functionallycorrelated controls that may be operated without looking at them, tokeep the driver's head up during driving. The system communicatesspecific commands to surrounding traffic, which increases both thesafety and utility of operation. The system also permits the functionalmodes of the light bar and siren to be programmed in accordance withdepartment policies instead of requiring officers to make safetydecisions under field conditions. The result is that the presentinvention creates an integrated system that improves effectiveness andsafety in the operation of all emergency vehicles, including police,fire and road maintenance vehicles.

I claim:
 1. A light bar system for a motor vehicle including:a plurality of forward-facing lights and a plurality of rear-facing lights arranged in a light bar having a right-hand end and a left-hand end on a line perpendicular to the length of the vehicle; a means for sequentially operating the forward-facing lights in a pattern moving from one light to the next light in a pattern in a preferred right-hand or left-hand direction; a means for simultaneously operating the rear-facing lights in a pattern moving from one light to the next light in a pattern in the direction opposite that of the forward-facing lights.
 2. A light bar system according to claim 1 in which the means for sequentially operating the lights is a frequency modulating ramp generator producing an electrical ramp signal of linearly changing audio frequency between a high and low acoustic pitch;a frequency divider means for selecting a series of time-spaced frequency bands in the changing frequency ramp signal; and a light selection means for operating at least one specific forward-facing light and one specific rear-facing light in the light bar at each selected frequency band of the ramp signal.
 3. A light bar system according to claim 2 in which the ramp signal is a generally linear bidirectional undulation pattern also operating an acoustic siren in a wail mode of successive increasing and decreasing frequencies.
 4. A light bar system according to claim 2 in which the ramp signal is a saw-tooth pattern linearly increasing from a low audio frequency to a high audio frequency, also driving an acoustic siren in a yelp mode of repeated successive frequency modulating ramps of increasing frequencies.
 5. A light bar according to claim 12 or 13 in which the lights in the light bar are sequentially operated by switching in a pattern in synchronism with the siren in which the lowest selected frequency of the frequency modulating ramp generator produces an electrical ramp signal of changing frequency and the means for selecting a series of time-spaced frequency bands in the changing frequency ramp signal operates a light at the center of the light bar, in which the lowest selected frequency operates the two forward-facing lights and the two rear-facing lights nearest the center of the light bar, each successive higher frequency operating the next adjacent light in each direction from the center lights, and the highest frequency operating the light at each end of the light bar; whereby the ramp signal results in an illumination pattern that sequentially switches symmetrically between the center and both ends of the light bar in synchronism with the siren; wherein a siren wail signal sequentially switches the illumination pattern from the center of the light bar to both ends with the increasing siren frequency and then back to the center with the decreasing siren frequency, and a yelp signal sequentially switches the illumination pattern from the center of the light bar to both ends with increasing siren frequency and then begins again at the center at the lower frequency of the yelp signal.
 6. A light bar according to claim 3 or 4 in which the forward and rear-facing lights in the light bar are sequentially operated by switching in a pattern in which the lowest selected frequency of the frequency modulating ramp generator producing an electrical ramp signal of changing frequency and the means for selecting a series of time-spaced frequency bands in the changing frequency ramp signal operates a light at one end of the light bar, each successive higher frequency band operates the next sequential light in the pattern across the light bar, and the highest frequency band operates the light at the opposite end of the light bar; and a wail mode ramp signal produced by said ramp generator produces an illumination pattern that sequentially switches back and forth between the opposite ends of the light bar synchronously with the siren wail signal.
 7. A light bar according to claim 3 or 4 in which the forward and rear-facing lights in the light bar are sequentially operated in a pattern in which the lowest selected frequency of the frequency modulating ramp generator producing an electrical ramp signal of changing frequency, including means for selecting a series of time-spaced frequency bands in the changing frequency ramp signal operates a light at one end of the light bar, each successive higher frequency operates the next sequential light in the pattern across the light bar, and the highest frequency operates the light at the opposite end of the light bar; and a yelp mode ramp signal produced by said ramp generator produces an illumination pattern that sequentially switches repeatedly in the same direction from one end to the opposite end of the light bar synchronously with the siren yelp signal.
 8. A light bar system according to claims 3 or 4 in which the ramp signal of linearly changing audio frequency has an electric switch means operable by a horn button of the motor vehicle and also includes a means for doubling the number of ramps generated per unit of time.
 9. A light bar according to claim 3 or 4 in which the lights in the light bar are sequentially operated in a pattern in which the lowest selected frequency band operates a light at one end of the light bar, each successive higher frequency band operates the next sequential light in the pattern, and the highest frequency band operates the light at the opposite end of the light bar; including an electrical switching means operable by the left-turn signal selector of the motor vehicle to operate a sequentially operated illumination pattern in which the forward-facing lights sequentially switch from the right-hand end of the light bar to the left-hand end and the rear-facing lights sequentially switch from the left-hand end of the light bar to the right-hand end; and operable by the right-turn signal selector of the motor vehicle in which the forward-facing lights sequentially switch from the left-hand end of the light bar to the right-hand end and the rear-facing lights sequentially switch from the right-hand end of the light bar to the left-hand end.
 10. A light bar system for a motor vehicle including:a plurality of forward-facing lights and a plurality of rear-facing lights arranged in a light bar having a right-hand end and a left-hand end on a line perpendicular to the length of the vehicle; a means for sequentially operating the lights in a pattern moving from one light to the next light in a pattern in a preferred right-hand or left-hand direction along the light bar; the means for sequentially operating the lights including a frequency modulating ramp generator producing an electrical ramp signal of linearly changing audio frequency between a high and low acoustic pitch, a frequency divider means for selecting a series of time-spaced frequency bands in the changing frequency ramp signal and a light selection means for operating at least one specific forward-facing light and one specific rear-facing light in the light bar at each selected frequency band.
 11. A light bar system according to claim 10 in which the ramp generator additionally drives a siren.
 12. A light bar according to claim 11 in which the lights in the light bar are sequentially operated by switching in a pattern in synchronism with the siren in which the lowest selected frequency operates the two forward-facing lights and the two rear-facing lights nearest the center of the light bar, each successive higher frequency operating the next adjacent light in each direction from the center lights, and the highest frequency operating the light at each end of the light bar; whereby the ramp signal results in an illumination pattern that sequentially switches symmetrically between the center and both ends of the light bar in synchronism with the siren; wherein a siren wail signal sequentially switches the illumination pattern from the center of the light bar to both ends with the increasing siren frequency and then back to the center with the decreasing siren frequency, and a yelp signal sequentially switches the illumination pattern from the center of the light bar to both ends with increasing siren frequency and then begins again at the center at the lower frequency of the yelp signal. 